Warning: --data is not valid JSON — event will be emitted wi

Error message

Warning: --data is not valid JSON — event will be emitted without data payload: ${rawData}

What it means

The archon CLI 'workflow event emit' command (packages/cli/src/cli.ts:1054) parses the --data flag as JSON. When parsing fails it does not abort: it prints this warning and emits the event with no data payload (eventData stays undefined), so downstream nodes waiting on the event receive an empty data object.

Source

Thrown at packages/cli/src/cli.ts:1054

                jsonFlag,
                'Usage: archon workflow event emit --run-id <run-id> --type <event-type>\n' +
                  'Error: --type is required'
              );
            }
            if (!isValidEventType(eventType)) {
              const { WORKFLOW_EVENT_TYPES } = await import('@archon/workflows/store');
              return await fail(
                jsonFlag,
                `Error: unknown event type: ${eventType}\nValid types: ${WORKFLOW_EVENT_TYPES.join(', ')}`
              );
            }
            let eventData: Record<string, unknown> | undefined;
            const rawData = values.data as string | undefined;
            if (rawData) {
              try {
                eventData = JSON.parse(rawData) as Record<string, unknown>;
              } catch {
                console.warn(
                  `Warning: --data is not valid JSON — event will be emitted without data payload: ${rawData}`
                );
              }
            }
            await workflowEventEmitCommand(runId, eventType, eventData, effectiveCwd);
            break;
          }

          case 'install': {
            const installSlug = positionals[2];
            if (!installSlug) {
              return await fail(jsonFlag, 'Usage: archon workflow install <slug> [--force]');
            }
            const forceFlag = values.force as boolean | undefined;
            await workflowInstallCommand(installSlug, effectiveCwd, forceFlag);
            break;
          }

View on GitHub (pinned to 0773b97458)

Solutions

Quote the whole --data value and use valid JSON: --data '{"key":"value"}'
Build the payload with a JSON serializer (jq -n, JSON.stringify) instead of hand-writing it
Check the warning output: the raw value is echoed, so inspect what the shell actually passed
If the event legitimately needs no payload, omit --data instead of passing malformed JSON

Example fix

// before
archon workflow event emit $RUN done --data status=ok
# after
archon workflow event emit $RUN done --data '{"status":"ok"}'

Defensive patterns

Strategy: validation

Validate before calling

// Validate --data before invoking the CLI:
const raw = process.argv[process.argv.indexOf('--data') + 1];
if (raw !== undefined) JSON.parse(raw); // throws early with a clear message
// shell: jq -n --arg s ok '{status: $s}' to build the payload

Type guard

function isValidJsonObject(raw) {
  try { const v = JSON.parse(raw); return typeof v === 'object' && v !== null && !Array.isArray(v); }
  catch { return false; }
}

Try / catch

// The CLI itself warns and continues (fallback: no data payload). To make it fatal:
const raw = getValue('--data');
if (raw !== undefined && !isValidJsonObject(raw)) {
  throw new Error(`--data must be valid JSON, got: ${raw}`);
}
await workflowEventEmitCommand(runId, eventType, eventData);

Prevention

Single-quote the entire --data value in shell so inner quotes survive
Build payloads with jq -n or JSON.stringify instead of hand-writing JSON
Remember the failure is silent-ish: the event still emits with no data, breaking waiters
Omit --data entirely when the event needs no payload

When it happens

Trigger: Running a CLI command like `archon workflow event emit <runId> <eventType> --data '...'` where the --data value is not valid JSON — unquoted shell values, keys without quotes, single quotes inside the value, or shell word-splitting truncating the payload.

Common situations: Passing --data foo=bar instead of JSON; shell stripping inner quotes so JSON.parse fails; hand-built JSON with smart quotes; forgetting to wrap the value in single quotes so spaces split arguments.

Related errors

AI-assisted analysis of coleam00/Archon@0773b97458 (2026-09-01). Data as JSON: /api/errors/0002313aacec8027. Report an issue: GitHub.